Intermittent wheel brake



July 6,

Filed Feb. 23, 1951 INTERMITTENT WHEEL BRAKE 2 Shee ts-Sheet 1 a vINVENTOR.

Ronald dfilaggh BY v 6W0" n v v 32 y 1954 R. s. BLOUGH INTERMITTENTWHEEL BRAKE 2 Sheets-Sheet 2 Filed Feb. 23. 1951 INVENTOR. Ronald S.Blou 1) Patented July 6, 1954 UNITED STATES PATENT OFFICE mesneassignments, to Philco Corporation,

Philadelphia, Pa., a corporation of Pennsyl- Vania Application February23, 1951, Serial No. 212,459

3 Claims.

The invention relates to drive mechanisms for washing machines and moreparticularly to mechanisms of the type utilized to oscillate a washingelement such, for example, as an agitator.

Drive mechanisms of the above general character are usually arranged toimpart positive movements to the oscillating element, turning theelement first in one direction through a predetermined angle and thenreversing to turn it in the opposite direction through the same angle.As the washing element oscillates the washing load, that is, the mass ofclothes and water acted on by the element, oscillate with it. However,when the movement of the element is interrupted prior to its change indirection at each end of the oscillatory stroke, the washing loadcontinues to move along in the same direction and tends to carry theelement with it. In other words, the inertia of the washing load exertsa 1.

force on the washing element tending to make the element overrun themechanism which drives it. The result is that the backlash between themoving parts is suddenly taken up and a sharp knock or otherobjectionable noise is produced.

Careful machining and fitting of the parts may reduce but does notcompletely eliminate the noises above referred to since some backlash isinherently present due to the necessity of providing a running fitbetween the parts. It has, therefore, become a common practice toprovide some type of braking means acting on the oscillating element toprevent it from being carried along with the water and washing load.Such braking means effectively eliminate or substantially reduce thenoise, but as heretofore constructed they exert a constant drag on theelement which is objectionable for obvious reasons.

With the above in view, one object of the invention is to provideimproved means for preventing overrun of the oscillating element at theends of its oscillatory stroke without imposing a constant drag oneither the element or the driving mechanism.

Another object is to provide braking mechanism for an oscillatingelement which leaves the element free of' restraint during the majorportion of its oscillatory stroke and exerts an effective braking forcethereon as the element approaches either end of its stroke, thuseffectively eliminating backlash between the parts and the objectionablenoise resulting therefrom.

A more specific object is to provide knock eliminating means for washingmachine drive mechanisms of the above general character which is simplein construction and inexpensive to manufacture, which is subject to aminimum of wear in use and which is efficient and reliable in operation.

Other objects and advantages of the invention will become apparent fromthe following detailed description of the preferred embodimentsillustrated in the accompanying drawings, in which:

Figure 1 is a fragmentary sectional View of an agitator type washingmachine equipped with knock eliminating means embodying the features ofthe invention.

Fig. 2 is a sectional view of the lower end of the agitator drive shafttaken in a vertical plane through the axis of the shaft. I

Fig. 3 is a sectional view taken in a plane substantially on the line 33of Fig. 2.

Fig. 4 is a fragmentary sectional view of the agitator drive shaftequipped with a modified form of the knock eliminator.

Fig. 5 is a sectional View taken in a plane substantially on the line 55of Fig. 4.

Fig. 6 is an exploded perspective view showing details of the partsutilized in the knock eliminator shown in Figs. 4 and 5.

While the invention is susceptible of various modifications andalternative constructions, I have shown in the drawings and will hereindescribe in detail the preferred embodiment, but it is to be understoodthat I do not thereby intend to limit the invention to the specific formdisclosed, but intend to cover all modifications and alternativeconstructions falling within the spirit and scope of the invention asexpressed in the appended claims.

For purposes of illustration, the invention has been shown asincorporated in a washing machine having a tub I0 with a centrallydisposed agitator I I mounted therein. The tub is enclosed in a housingI2 and, in this instance, is seated on a ring l3 of resilient materialcarried by a part of the housing. The agitator II as shown is ofconventional construction comprising an upright tubular central portionH terminating at its lower end in an outwardly flaring skirt portion 15.A series of vanes I6 extend radially from the central portion and overthe skirt portion of the agitator.

()scillatory movements are imparted to the agitator l l by a shaft 2i)driven by suitable power drive means including a transmission 2!supported on the housing l2 below the tub Hi. In the particular machineillustrated the shaft 29 extends upwardly from the transmission 2|through an opening in the bottom of the tub and through an uprighthollowcolumn 22 secured to the tub bottom. This column carries a bearingsleeve 23 at its upper end for journalling the shaft 2i! adjacent itsupper end and also has an external seat for a bearing 24 which guidesthe agitator l i in its oscillatory movements. The shaft 28 is arrangedto project from the upper end of the column 22 and is drivinglyconnected with the agitator I l by a suitable coupling mem- I ber 25.

As shown in Fig. 1 of the drawings, the transmission 2! is enclosed in acasing comprising a an-like bottom member 26 in the form of a castingand a top member 27 which may conveniently comprise a sheet metalstamping. The shaft extends through the top member 21 of the casing andits lower end is journaled in a bearing recess 28 formed in a boss 29integral with the bottom member 26. A ball thrust bearing Sii seated inthe bottom of the recess 28 supports the shaft and agitator assembly. Inthe present instance the shaft 29 is provided with an intermediatebearing 3| carried by a bracket 32 interposed between the bottom of thetub ii and the top of the transmission casing and serving in thisinstance to support the casing from the tub.

The transmission 2i shown by way of illustration is generally similar tothat disclosed in the Risor Patent No. 2,267,577 issued December 23,1941. Briefly, the transmission comprises a main driving element in theform of a gear 35 rotatably mounted on a vertical stud supported by thebottom member 2% of the transmission casing. The gear in thisinstance isin the form of a worm wheel adapted to be driven by a worm 3"! which, inturn, is driven by an electric motor (not shown) mounted externally ofthe casing.

The drive gear 35 is provided with a crank pin 32 upon which isjournalled one end of a pitznan 2359. The other end of the pitman ispivotally connected to an intermediate drive member pivoted at one endby a pin iii on the bottom member 26 of the At its other end theintermediate drive member 563 is formed with teeth defining a segmentalrack ii: adapted to mesh with the teeth a pinion Q3 rotatably mounted onthe lower end of the agitatorshaft 2E shaft into or out of engagingrelation with teeth formed on a clutch member or collar pinned orotherwise n.on-1otatably fixed to the shaft. A spring interposed betweena collar it on the shaft the upper end of the pinion ii, urges thelatter downwardly to engage theclutch and thus effect a drivingconnection between the transmission and the agitator shaft. Thisconnection may be interrupted by shifting the pinion upwardly, theshifting being effected through the medium of a vertically slidableshifter arm actuated by a rotatable operating member 48 accessible fromthe exterior of the machine.

It will be apparent that with the above construction rotation of themain drive gear will impart a rocking or oscillating movement to theintermediate d .ve member 3%? and suchniovement will imparted to theshaft 253 through the rack 52, pinion i3 and clutch member Mi. Theamplitude of the osciilating movements is determined, of course, by thethrow of the crank pin 58 and the driving ratio provided by the raclrand pinion connection. While the oscillation may be of anydesired'amplitude, it is usually-greater than 180 but less than 360. At

The pinion is also slidable axially of the r the beginning of a strokein either direction the rotational speed of the agitator shaft graduallincreases and through the action of the agitator the washing load isstarted to rotate in the same direction. After passing the midpoint ofits stroke, the speed of rotation of the shaft gradually decreasespreparatory to reversal in the direction of rotation.

During the decreasing speed of rotation and particularly as the end ofthe oscillatory stroke is approached, the inertia of the washing loadexerts a force 'on the agitator tending to drive the pinion asfasterthan the rack 42. The backlash between the rack and pinion as wellas play between other .parts of the mechanism is thus taken up while theparts are moving relatively rapidly with the production of anobjectionable knock.

In accordance with the invention the tendency of the pinion 53 tooverrun and the knock resulting therefrom is eliminated by applying tothe oscillating element a braking force of suincient amplitude toprevent continued movement of the element independently of the drivemechanism as the element approaches opposite ends of its stroke. Moreparticularly the braking force is applied through only a small portionof the stroke adjacent each end thereof, leaving the element free ofrestraint throughout the major portion of its stroke, to the end that,smooth and silent running of the machine is insured and at the same timewaste of power is avoided and wear on the cooperating parts of thebraking means is substantially-reduced.

One arrangement for applying the braking force in the novel manner abovereferred to is shown in Figs. 1-3 of the drawings. In the constructionthere shown a part fixed to the shaft 253, in this instance the clutchmember M, is formed to provide an axially facing braking surface 56against which a friction member 5! is continuously yieldablypressediasby a washer 52 and spring 53. The friction member .iil .may bein the form of an annuluszof suitable frictionmaterial and is mounted onthe shaft between the braking surface 50 and the washer 52. In theparticular embodiment illustrated the-spring 53' is interposed betweenthe lower face of the washer 52 and a pinttanchored in the shaft-2e.

Due to the continuous frictional engagement between the member 5| andbraking surface 5 the friction member 51 tendsto oscillate with theshaft 2!). To apply thezbraking force to-the shaft as it approachesopposite ends of its oscillatory stroke, provision is -made forinterrupting the movement of .the friction member 51 before the shaftreachesthe end of its strolze so as to produce relative movement betweenthe frictionally engaged members. For this purpose the friction member5! is formed with a radially projecting finger 55 engageable alternatelywithpins 5t and 5'! anchored to the casing 28 in predetermined angularspaced relation with respect to the axis of the shaft 2!]. In theparticular embodiment illustrated in which the agitator is oscillatedthrough a strokeof something less than 360, the pinsSS ancl'fi'i arelocated-at diametrically opposite sides of the shaft, thus allowing thefriction memberlil to swing through an arc of 180. To minimize wear thefinger may be conveniently fitted with a metal bushing 58 for engagementwith the pins, as shown :in Fig. 3.

With theabove arrangement washing element H is left .free of restraintthroughout 180-ofits oscillatory stroke and, at each end .of thestroke,

interruption of the rotation of the friction member 52 applies a brakingforce opposing continued movement of the element in the ame direction.The drive mechanism, of course, continues to positively turn the shaft21'! to carry the washing element to the end of its oscillatory strokebut movement beyond that limiting position independently of the drivemechanism is prevented by the frictional resistance between the members5|, 52 and 4 5. Accordingly, the inertia of the washing load isineffective to advance the washing element faster than the element ismoved by the drive mechanism or, in other words, overrunning of the rack62 by the pinion 43 is precluded.

In the modified construction shown in Figs. 4-6, a braking force islikewise applied to'the shaft 29 as the washing element approachesopposite ends of its stroke by the relative movement of two continuouslyengaged friction elements, one associated with the shaft and the otherwith a stationary part of the machine. In this instance the bottommember 26 of the casing is formed with a counterbore disposed coaxiallyof the bearing recess 23 for the shaft and defining a cylindricalbraking surface 66. Confined within the counterbore and in frictionalengagement with the braking surface 66 is a resilient band 6| of steelor other suitable material. Opposite end portions of the band are bentinwardly to form radially disposed abutments 62 and 63 engageablealternately with spaced abutments in the form of lugs 64 and 65 formedon or rigidly secured to the clutch member 44. The bent ends 62 and 63of the band 6| may be reinforced by relatively heavy strips 66 of metalwelded or otherwise suitably attached to the ends.

In practice the lugs 6d and 65 are spaced apart circumferentially of theclutch member 44 so as to engage the abutments 62 and 63 as the washingelement l I approaches opposite ends of its oscillatory stroke. Thearrangement is such that during the latter portion of the stroke theband is carried along with the shaft and due to its frictionalengagement with the braking surface 60 it opposes the movement of theshaft with a force of suflicient amplitude to prevent the shaft frombeing advanced by the action of the washing load on the washing element.Reverse movement of the shaft is unrestrained until it again approachesthe end of its oscillatory stroke, whereupon the other lug on the collarengages the companion abutment on the band 6| to again produce arelative movement between the band and the cooperating braking surface60. Thus the braking force i applied at each end of the oscillatorystroke of the washing element, yet the element is free of restraintthroughout the major portion of its stroke.

It will be apparent from the foregoing that the invention provides knockeliminating means of novel and advantageous construction for washingmachines of the type equipped with an oscillating washing element. Thebraking force for attaining this result, that is, for preventing theoscillating element from overrunning the drive mechanism is applied in anovel manner only at the ends of the oscillatory stroke, leaving theelement free of restraint throughout the major portion of its stroke.Smooth, quiet operation is thus obtained without waste of power and witha minimum of wear on the moving parts of the machine.

I claim as my invention:

1. In a washing machine having an element supported for oscillation,drive mechanism connected to and operative to oscillate said elementthrough an angle of predetermined amplitude, means defining a stationarybraking surface, a member in frictional engagement with said surabutmentmeans oscillatable with said element positioned to engage said memberand shift it relativeto said braking surface as said element approacheseitherend of its oscillatory stroke, the frictional resistance betweensaid member said braking surface being of sufficient magnitude toprevent the element from being carried along by the inertia of the loadacting on the element.

2. The combination with a shaft and means for rotating it alternately inopposite directions through an angle of less than 360, a collar fixed toand rotatable with said shaft, a stationary member presenting a brakingsurface concentric with said shaft, a movable member having a brakingsurface in frictional engagement with the surface of said stationarymember, abutment means on said movable member, and abutment means onsaid collar cooperating with the abutment means on said movable memberto shift the same relative to said stationary member, said abutmentmeans being positioned so as to leave the shaft free of restraintthroughout the major portion of its rotational movement in eitherdirection.

3. In a washing machine, in combination, a shaft, a casing having abearing journaling said shaft, drive mechanism in said casing operativeto rotate the shaft alternately in opposite directions through an angleof less than 360, a collar mounted on and rotatable with said shaft,said casing having a counterbore positioned to receive said collar anddefining a cylindrical braking surface concentric with said shaft, aresilient band confined in said counterbore in frictional engagementwith said braking surface, said band having opposite end portions bentinwardly to form radially disposed abutments, and lugs formed on saidcollar defining spaced abutments engageable alternately with theabutments on said band as the shaft approaches its limit positions ofrotation.

References Cited in the file of .this patent UNITED STATES PATENTSNumber Name Date 2,185,109 Williams Dec. 26, 1939 2,273,566 Faber Feb.17, 1942 2,294,516 Smith Sept. 1, 1942 2,538,620 Heinrich Jan. 16, 1951FOREIGN PATENTS Number Country Date 189,927 Switzerland June 1, 1937

